SET IDENTITY_INSERT Persona ON

insert into Persona ( Id, Nombre, Paterno)
	select p.BusinessEntityId, p.FirstName, p.LastName	
		from AdventureWorks2012.Person.Person p			
		where LastName like 'a%'
			and p.BusinessEntityID not in (
											select Id
												from Persona					
											)

SET IDENTITY_INSERT Persona OFF

go
use [NORTHWND]
go
declare @precio money
update Products SET
	@precio = UnitPrice = UnitPrice * 2
	where ProductID = 3

select @precio 

select *
	FROM  Products

select @precio = UnitPrice
	from Products
	where ProductID = 7

declare @Id int

select @Id = MAX(ProductID) 
	from Products
select @id
select @id = @id + 1
select @id
